A Study of Precision Forging of Steel Spur Gears: Upper Bound Model and Experiments

Precision forging process is widely used for the production of spur gears due to its advantages such as improved strength and surface finish, little waste of materials and reduction in the machining time of the gear. An important aspect of precision forging process is the load required to perform the process successfully and design the forging tools. In this research, a new kinematically admissible velocity field was presented to predict the precision forging pressure of the steel spur gear by upper bound analysis. The model considered the shape of tooth profile, the number of teeth and friction coefficient. The accuracy of the model was verified using experimental results and a good agreement was found between the two sets of results at the filling stage of the precision forging process. Also, the results were compared with the models developed by other researchers, showing that the teeth profile considered in this study was much closer to the actual profile of the gear.